This invention relates to integrated semiconductor devices and systems, and more particularly to features used in an electronic digital processing system which may employ a single-chip microprocessor or microcomputer device.
A description of the prior art is contained in U.S. Pat. No. 4,042,044, incorporated herein by reference.
It is the principal object of the invention to provide an improved microprocessor device and system, and an improved method of constructing and operating such apparatus. Another object is to provide improved performance or capabilities of a microprocessor or microcomputer while at the same time reducing the size (and thus cost) of the semiconductor device needed to implement the desired features. Further objects are to provide: a technique for executing instruction sequences in a microprocessor to emulate complex instructions which are indistinguishable from native instructions; a microprocessor which may be customized without employing micro-code programming; one which has on-chip memory, not included in the main memory map, for executing complex instructions; and improved emulator capability in a microcomputer.